From the Guidelines
Fasting can potentially cause hyperbilirubinemia, particularly in individuals with pre-existing conditions such as Gilbert's Syndrome.
Key Points
- Fasting may exacerbate Gilbert's Syndrome, leading to increased levels of unconjugated bilirubin in the blood 1.
- However, studies have shown that while initial increases in plasma unconjugated bilirubin concentration may occur in the first days of fasting, levels tend to decrease to basal values by the end of the fasting period 1.
- It is essential to consider the potential effects of fasting on liver function and bilirubin levels when evaluating patients with recurrent jaundice related to fasting, such as during Ramadan 1.
- The available evidence suggests that fasting may not have a sustained significant impact on bilirubin levels in individuals with Gilbert's Syndrome, but close monitoring is still recommended 1.
From the Research
Fasting and Hyperbilirubinemia
- Fasting has been recognized to cause hyperbilirubinemia, with the pathogenesis of this syndrome being unclear 2.
- Studies suggest that increased intestinal deconjugation and reabsorption of bilirubin may play a major role in the establishment of hyperbilirubinemia during fasting 2, 3.
- Fasting can also lead to a decrease in intestinal motility, resulting in the accumulation of bilirubin in the intestine and enhanced enterohepatic circulation, which can contribute to hyperbilirubinemia 3.
Mechanisms of Fasting-Induced Hyperbilirubinemia
- The uptake of bilirubin by the liver is not affected by fasting, with studies showing no difference in single-pass extraction of bilirubin and sulfobromophthalein (BSP) by livers from fasted animals compared to control animals 2.
- Fasting can lead to an increase in the intestinal content of total bile pigments, which can contribute to the development of hyperbilirubinemia 3.
- The pattern of individual bilirubin pigments during fasting can be used to identify constitutional hyperbilirubinemia, with an increase of more than 1 mg/dl in unconjugated bilirubin being associated with this condition 4.
Diagnosis and Evaluation of Hyperbilirubinemia
- Hyperbilirubinemia can be diagnosed by measuring fractionated bilirubin, which allows for determination of whether the hyperbilirubinemia is conjugated or unconjugated 5.
- A comprehensive medical history, review of systems, and physical examination are essential for differentiating potential causes of hyperbilirubinemia, such as alcoholic liver disease, biliary strictures, choledocholithiasis, drug-induced liver injury, hemolysis, or hepatitis 5.
- Initial laboratory evaluation should include assays for bilirubin, complete blood cell count, aspartate transaminase, alanine transaminase, gamma-glutamyltransferase, alkaline phosphatase, albumin, prothrombin time, and international normalized ratio 5.